In the art of smokeless flaring of smoke-prone gases, where steam for smoke suppression is not available, it is common to use air powered flares, where blowers supply air as required.
Such flares, whether vertically or horizontally oriented, have a serious fault in that at times the effects of wind turbulence, or wind impact, cause movement of flame and hot gases from the normal burning area, downstream of the burner, in an inverted direction, through the air tube between the burning area and the blower, which is typically motor-driven. This may cause serious heat damage to both blower and motor. Flares have been made inoperable in such cases.
Where the flare is horizontally oriented, and where the blower induced air flow velocity from the blower over the burner is of the order of 83 fps, for discharge countercurrent to wind action, where the wind action may be at a velocity of 88 feet/second (60 MPH) which is not at all uncommon, the wind impact pressure exceeds the blower air discharge pressure and in this case forces the flame and hot gases from the normal burning area back through the air tube and into contact with the blower and motor.